Browning Susceptibility and Changes in Composition During Storage of Carambola Slices

Browning and changes in the composition of sliced and whole carambola (Averrhoa carambola L.) fruit during storage were investigated. Susceptibility to browning after slicing, packaging and storage for 4 wk at 4.4°C varied considerably between four cultivars and five selections. There was no difference in browning susceptibility between fruit harvested at mature green or breaker stages of maturity. Freshly sliced carambola browned only slightly when exposed to air, but packaged slices that had been stored for 2 or more wk at 4.4°C browned rapidly (within 6 hr) when exposed to air. Whole fruit stored at 4.4°C for up to 6 wk, then sliced, showed much less susceptibility to browning. Ascorbic acid decreased and polyphenoloxidase activity increased in carambola slices during storage, but less in whole fruit. Treating slices with 1.0 or 2.5% citric acid + 0.25% ascorbic acid (in water) prior to packaging was very effective in limiting browning.     

Osmotic dehydration of guava: influence of replacing sodium metabisulphite with honey on quality

Guava slices were subjected to pre-treatment by soaking in a solution containing 0.25% (w/v) sodium metabisulphite, 0.5% (w/v) ascorbic acid, 1% (w/v) citric acid, 1% (w/v) calcium chloride and either 0%, 1% or 3% (v/v) honey. A higher concentration of metabisulphite [0.5% (w/v)], but no honey, was also prepared as a reference. After osmotic dehydration, the guava slices were dried at 60 °C. During 24 weeks of storage, the measured texture values of products indicated that an addition of honey significantly delayed the increase in hardness and cutting work in guava slices compared to other treatments ( P  ≤   0.05). Pre-treatment with 0.5% (w/v) metabisulphite without honey or 0.25% (w/v) metabisulphite with 1% (v/v) honey maintained colour during storage better than with 0 or 3% (v/v) honey. The result showed good agreement with colour score evaluation. Overall results suggested that 1% (v/v) honey was the best pre-treatment condition.     

CARAMBOLA QUALITY AFTER HEAT TREATMENT,COOLING AND STORAGE1

Various cooling methods following heat treatment were investigated to reduce injury to carambola (Averrhoa carambola L.) caused by heat stress. Cooling fruit with ice water (IW) caused more severe degradation to carambola quality compared with ambient air (AA), ambient water (AW) or refrigerated air (RA). Cooling fruit after heat treatment with RA at the targeted storage temperature (10C) resulted in the least damage to carambola. Refrigerated air, AA, and AW caused similar degradation such as peel pitting, bronzing, decay and weight loss, but AA cooled fruit were the least firm, and AW cooled fruit had the least preferred flavor. At the end of 7 days of storage, fruit heated with hot water (HW) were less yellow than vapor heat (VH)‐treated fruit, and fruit cooled by AA were more yellow than those cooled by other methods. There was no difference in peel color, total soluble solids, titratable solids, pH, or mastication texture of pulp among treatment combinations. Carambolas cooled with refrigerated air had the least injury compared with other cooling methods evaluated.     

SHELF-LIFE EXTENSION OF TILAPIA IN CRUSHED ICE WITH ADDITIVES AT −3C

Thirty-six experiments were carried out with potassium sorbate, citric acid and ascorbic acid at 0, 0.1, 0.15 and 0.2% in separate and mixed forms added to water to produce ice for storing tilapia at −3C for 15 days. Every three days chemical indicators trimethylamine and hypoxanthine as well as psychrotrophic bacteria counts were determined.
Fish stored in crushed ice with additives have markedly lower changes in trimethylamine and hypoxanthine with storage compared to iced controls. By linear regression analysis of 36 treatments, the following six treatments were best: 0.2% ascorbic acid, 0.15 or 0.2% citric acid, and 0.1, 0.15 and 0.2% potassium sorbate. These six treatments were not statistically different due to trimethylamine, hypoxanthine content nor due to psychrotrophic bacteria growth during storage. Probably, the treatment with the lowest concentration of citric acid (0.15%) and potassium sorbate (0.1%) should be considered as the best.     

Prevention of enzymatic browning of apple cylinders using different solutions

Inhibition of enzymatic browning and decay on cut surfaces of Golden Delicious apple using ascorbic acid, cysteine, sodium chloride, calcium chloride, citric acid and sodium ascorbate alone or in combinations was investigated at 4 and 10 °C for a storage period of 0, 7 and 14 days, in an attempt to find the most effective treatment. Apple segments immersed in ascorbic acid and citric acid alone showed visual traces of browning after 7 days storage at 4 °C. After 14 days storage, only ascorbic acid and ascorbic acid plus sodium chloride had moderate browning, while all other treatments were severely affected. However, at 10 °C, only ascorbic acid was effective in reducing the level of browning, although its effect was minimal after 14 days storage. Browning was more severe at 10 °C than 4 °C in all solutions. The browning measurement (a* value) became increasingly positive from 7‐ to 14‐day storage. Microbial decay was absent in all treatments within 7 days at 4 and 10 °C. However, three test solutions showed microbial decay after 14 days storage at 10 °C in addition to the control solution, which showed decay at both 4 and 10 °C storage temperatures.     

Comparison of calcium lactate with chlorine as a washing treatment for fresh‐cut lettuce and carrots: quality and nutritional parameters

The efficacies of calcium lactate and chlorine washing treatments of fresh‐cut lettuce and carrots were compared during storage at 4 °C over 10 days. The gas composition of packages, colour, enzyme activity, texture, sensory attributes, microflora and levels of ascorbic acid and carotenoids were evaluated at 1, 3, 7 and 10 days. Calcium lactate treatment was not significantly different to chlorine treatment (p < 0.05) in terms of maintaining colour, texture and acceptability of fresh‐cut lettuce and carrots during the entire storage period. The washing treatments did not affect levels of ascorbic acid of fresh‐cut lettuce or carrots. Carotenoid levels were higher in calcium lactate‐treated carrots than chlorine‐treated samples at the end of storage. Mesophilic, psychrotrophic and lactic acid bacteria counts were not significantly different between treatments for both vegetables. Copyright © 2005 Society of Chemical Industry     

Inactivation of Salmonella during drying and storage of apple slices treated with acidic or sodium metabisulfite solutions

This study was undertaken to determine whether pretreating inoculated Gala apple slices with metabisulfite or acidic solutions enhanced the inactivation of Salmonella during dehydration and storage. Apple slices inoculated with a five-strain mixture of Salmonella (7.6 log CFU/g) were pretreated, dried for 6 h at 60 degrees C, and stored aerobically at 25 degrees C for 28 days. Predrying treatments included (i) no treatment, (ii) 10 min of immersion in sterile water, (iii) 10 min of immersion in a 4.18% sodium metabisulfite solution, (iv) 10 min of immersion in a 3.40% ascorbic acid solution, and (v) 10 min of immersion in a 0.21% citric acid solution. Samples were plated on tryptic soy agar with 0.1% pyruvate (TSAP), brilliant green sulfa (BGS) agar, and xylose lysine tergitol 4 (XLT4) agar for the enumeration of bacteria. Populations were not significantly (P > 0.05) reduced by immersion in water but were reduced by 0.7 to 1.1 log CFU/g by immersion in acidic solutions. Immersion in the sodium metabisulfite solution reduced populations by 0.4, 1.3, and 5.4 log CFU/g on TSAP, BGS agar, and XLT4 agar, respectively. After 6 h of dehydration at 60 degrees C, populations on untreated and water-treated slices were reduced by 2.7 to 2.8, 2.7 to 2.9, and 4.0 to 4.2 log CFU/g as determined with TSAP, BGS agar, and XLT4 agar, respectively. In contrast, populations on slices treated with sodium metabisulfite, ascorbic acid, and citric acid were reduced after 6 h of dehydration by 4.3, 5.2, and 3.8 log CFU/g, respectively, as determined with TSAP; by 4.7, 5.5, and 3.9 log CFU/g, respectively, as determined with BGS agar; and by 5.5, 5.7, and 5.6 log CFU/g, respectively, as determined with XLT4 agar. Bacteria were still detectable by direct plating after 28 days except on slices treated with ascorbic acid. Immersion in metabisulfite or acidic solutions prior to dehydration should enhance the inactivation of Salmonella during the dehydration and storage of Gala apple slices.     

Quality Index, Consumer Acceptability, Bioactive Compounds, and Antioxidant Activity of Fresh-Cut "Ataulfo" Mangoes (Mangifera Indica L.) as Affected by Low-Temperature Storage

ABSTRACT:  To measure bioactive compound losses due to minimal processing, mature green fresh-cut mangoes ( Mangifera indica L.) cv. "Ataulfo" were subjected to an antioxidant treatment and stored at 5 °C during 15 d. Quality index, total phenols, flavonoids, β-carotene, ascorbic acid, vitamin E, and antioxidant activity were measured during the storage period of fruits. Antioxidant capacity was estimated using ORAC_FL, TEAC, and DPPH assays. The dipping treatments with ascorbic acid (AA) + citric acid (CA) + CaCl₂ affected positively quality delaying deterioration of fresh-cut mango as compared with whole fruit. However, dipping treatment affected the consumer preferences of fresh-cut mangoes. The highest vitamin C, β-carotene, and vitamin E losses were observed after 10 d, being similar in whole and fresh-cut mangoes. The antioxidant activity was not significantly affected by storage time. We conclude that fresh-cut mangoes retained their bioactive compound content during storage and their antioxidant and nutritional properties make them a good source of these compounds.     

The effects of washing treatment on antioxidant retention in ready-to-use iceberg lettuce

The influence of washing treatment on the retention of key antioxidants in minimally processed iceberg lettuce was examined. Shredded iceberg lettuce was subjected to one of three washing treatments: a domestic wash (tap-rinsed), immersion in distilled water (water-dipped) or immersion in chlorinated water (chlorine-dipped). Lettuce was subsequently packed in oriented polypropylene bags and flushed with 100% nitrogen and stored at 4 °C. Vitamin C (ascorbic acid and dehydroascorbic acid), total phenols, total antioxidants, individual phenols, individual carotenoids, colour measurements and pH were quantified on production day and throughout the storage period (8 days). Different groups of antioxidants were found to differ in their response to washing treatments. No significant ( P  > 0.05) effects of washing treatment were observed on total antioxidant activity, total phenolics and on the levels of individual phenolics (chicoric acid, chlorogenic acid and caffeic acid). Individual carotenoids were initially affected by washing treatment, with higher levels of lutein and beta-carotene retained with domestic washed lettuce. Ascorbic acid was the antioxidant most affected by washing treatments with domestic washing resulting in significantly ( P  ≤ 0.05) higher retention of ascorbic acid throughout the storage period compared with the chlorine-dipped lettuce.     

Kinetics of Frozen Stored Green Bean (Phaseolus vulgaris L.) Quality Changes: Texture, Vitamin C, Reducing Sugars, and Starch

ABSTRACT: Texture, vitamin C, reducing sugars, and starch quality changes of frozen green beans ( Phaseolus vulgaris L.) were studied for 250 d at storage temperatures of−7,−15, and−30 °C. All studied parameters suffered significant changes during frozen storage. Texture loss was described by a fractional conversion model, while ascorbic acid and starch evolution were successfully modeled with first-order reaction kinetics. Dehydro-ascorbic acid (DHAA) degraded only 8% during storage time, and thus frozen storage well preserves total vitamin C. The low estimated Arrhenius activation energies of texture, starch, and ascorbic acid losses emphasize that low temperatures do not substantially reduce degradation rates.     

Using mild heat treatment to improve the bioactive related compounds on fresh-cut green bell peppers

Bioactive related compounds of fresh-cut green bell peppers ( Capsicum annuum, L.) exposed to water immersion at 55 °C and 60 °C per 180 s were evaluated during storage. Their sensorial and microbial quality, acidity, sugar and chlorophyll content were also determined. Beneficial effects on sensorial attributes were observed in treated peppers with longer shelf life than in non-treated ones (5 days at 4 °C, 2 days at 10 °C). At the end of storage at 4 °C, phenols increased to 11% and quercetin and antioxidant capacity were retained, but in control peppers ascorbic acid dropped 16%. At 10 °C, there was no change in phenols; quercetin, ascorbic acid and antioxidant activity decreased (15%, 13% and 10% respectively) in treated peppers. Changes were more noticeable in non-treated products (phenols increased 21%, ascorbic acid decreased 28% and antioxidant activity 20%). Mild heat treatments applied to fresh-cut peppers seemed to preserve some of their bioactive compounds during storage.     

Enhancing aspalathin stability in rooibos (Aspalathus linearis) ready-to-drink iced teas during storage: the role of nano-emulsification and beverage ingredients, citric and ascorbic acids

BACKGROUND: The effects of citric and ascorbic acids on the stability of aspalathin in rooibos (Aspalathus linearis) ready‐to‐drink (RTD) formulations containing fermented rooibos extract (FR), aspalathin‐enriched green rooibos extract (GR) and aspalathin‐enriched green rooibos extract ascorbic acid solubilisate (GR‐solubilisate) were investigated during storage (12 weeks at 25 °C). RESULTS: Storage of iced tea formulations containing FR and GR extracts reduced their flavonoid content. The aspalathin content of FR iced tea without citric or ascorbic acid was reduced to undetectable levels by week 8 of storage. Addition of citric acid resulted in improved stability of aspalathin, but ascorbic acid did not impart additional stability. Iso‐orientin and orientin were less affected than aspalathin, presumably owing to partial conversion of aspalathin to these flavones. Similar results were obtained for GR iced tea formulations. Improved stability of aspalathin was noted in iced tea containing GR‐solubilisate with or without citric acid. Lower pH was shown to favour stability, especially for fermented rooibos iced teas. CONCLUSION: Citric and ascorbic acids contribute to the stability of rooibos flavonoids during storage. Differences in stability between formulations are not due to pH differences but may be related to the matrix. Copyright © 2011 Society of Chemical Industry     

ANTIOXIDANT ACTIVITY AND QUALITY OF MINIMALLY PROCESSED INDIAN CABBAGE (BRASSICA OLERACEA var CAPITATA)

The effect of different dip treatments and storage period on the antioxidant activity and biochemical quality of Indian cabbage for minimal processing was studied. A gradual decrease in total antioxidant activity was observed during storage at 6C with no detectable activity at the end of 9 days in all the dip treatments, except in treatments containing combination of ascorbic acid and citric acid, and ascorbic acid alone (10 g/L each). Possibility of considering antioxidant activity as a marker of shelf-life has also been proposed. Incorporation of ascorbic acid and citric acid in the dip water improved the overall appearance and retained the maximum antioxidant activity, ascorbic acid and total carotenoids. Based on the overall quality and appearance score, Golden Acre was found suitable for minimal processing with a shelf-life of 9 days.     

Storage quality of chopped garlic as influenced by organic acids and high‐pressure treatment

The storage quality of chopped garlic from bulbs in both dormant and dormancy‐terminated states with or without citric and/or ascorbic acids was investigated. The chopped garlic plus acids was also treated under high hydrostatic pressure (600 MPa, 1 min). Quality attributes of processed garlic during storage at 10 °C were evaluated in terms of colour, pH, polyphenol oxidase (PPO) activity, glucose content and viable cell count. Overall, the combined treatments with organic acids and high pressure conferred the best storage stability of chopped garlic, but the results depended on the physiological state of the raw garlic bulbs. For garlic from dormant bulbs, addition of citric acid rather than ascorbic acid or a mixture of the two inhibited browning more effectively. However, garlic from dormancy‐terminated bulbs, treated with organic acids or high pressure, turned green and then yellowish‐brown or brown. While the PPO activities of chopped garlic treated with organic acids or high hydrostatic pressure were reduced nearly to zero, other possible factors may affect the discolouration of chopped garlic. Concerning microbiological stability, the total viable cells in chopped garlic decreased significantly during storage owing to its own antimicrobial activity and the synergistic effect of high pressure. © 2001 Society of Chemical Industry     

Modified Atmosphere Packaging Affects Ascorbic Acid, Enzyme Activity and Market Quality of Broccoli

Reduced ascorbic acid (RAA) content, total chlorophyll and green color retention, enzyme activities and texture changes were followed in broccoli spears packaged in polymeric film and nonpackaged during 96 hr storage (10°C). Concentrations within packages monitored by gas chromatography were (CO₂,) 8% and (0²) 10%. RAA retention, moisture content, total chlorophyll and color retention were greater in packaged broccoli. No differences were found between packaged and nonpackaged broccoli for ascorbate oxidase and peroxidase activities, or texture.     

Effect of Combined Ozone and Organic Acid Treatment for Control of Escherichia coli O157:H7 and Listeria monocytogenes on Lettuce

ABSTRACT: This study was conducted to determine the effects of ozonated water (1, 3, and 5 ppm) alone with different exposure times (0.5,1,3, or5min), and combinations of 3 ppm ozone with 1% organic acids (acetic, citric, or lactic acids) during 1-min exposure for inactivating Escherichia coli O157:H7 and Listeria monocytogenes on lettuce and to observe the regrowth of these pathogenic bacteria on treated lettuce during storage for 10 d at 15°C. Results showed that 5 ppm ozone treatment for 5 min gave 1.09-log and 0.94-log reductions of E. coli O157:H7 and L. monocytogenes , respectively, indicating insignificant reductions compared with 3 ppm ozone treatment for 5 min. Treatment with 3 ppm ozone combined with 1 % citric acid for 1 min immersing resulted in 2.31 - and 1.84-log reductions ( P < 0.05), respectively. During storage at 15°C for 10 d after combined treatment and packaging, populations of E. coli O157:H7 and L. monocytogenes increased to approximately 9.0-log colony forming unit (CFU) /g, indicating that this treatment did not have a residual antimicrobial effect during storage. Although the storage study did not show control of these pathogens, the combined ozone-organic acid treatment was more effective in reducing population levels of these pathogens on lettuce than individual treatments.     

Protection of vessel permeability by genistein against lipopolysaccharide induced acute inflammation in a chick embryo chorioallantoic membrane model

Effects of dip treatments on nutritional quality preservation during the shelf life of fresh-cut tomato (Licopersicum esculentum Mill.) cv. Eufrates were investigated. Fresh-cut tomatoes were dipped in solutions of 2% ascorbic acid, citric acid, and calcium lactate for 2 min, then stored at 4°C for 20 days. Color (L*, a*, and b*), firmness, °Brix, phenolics, ascorbic acid content, antioxidant activity (DPPH), and sugars were measured during storage. Pathogen development was monitored, and a sensory evaluation was performed. Ascorbic acid was better in maintaining firmness. No treatments significantly affected °Brix, color, or sugars. Ascorbic acid maintained a higher antioxidant capacity, phenolics, and ascorbic acid content, and was better at reducing bacterial growth, while citric acid treatment was better at prevention of yeast and molds proliferation. Fresh-cut tomatoes showed good quality after 10 days of shelf life, except for flavor with the calcium lactate treatment. Ascorbic acid treatment better preserved the general and nutritional quality parameters.     

Effects of ascorbic and citric acid on beef lumbar vertebrae marrow colour

Citric acid was evaluated as a way of improving ascorbic acid’s ability to stabilize beef lumbar vertebrae colour in high-oxygen packaging (MAP; 80% O₂/20% CO₂). Vertebrae were treated with citric acid (1%, 3%, or 10%), ascorbic acid (1%, 3%, or 10%), or a combination of both. Citric acid demonstrated no positive effects (P > 0.05), compared with ascorbic acid, which inhibited (P < 0.05) discolouration throughout the 7d display. Although ascorbic acid inhibited discolouration (visual colour and a^∗; P < 0.05), 3% and 10% ascorbic acid were most effective. However, if vertebrae are displayed for less than 7d, there may be no significant colour-stabilizing advantages associated with increasing ascorbic acid from 3 to 10%. The significant oxidizing effects of citric acid at 10% were reversed (P < 0.05) by ascorbic acid. Combining citric and ascorbic acid had no synergistic affect (P > 0.05) on vertebrae colour.     

Biochemical changes in green sweet peppers during storage at different temperatures

The effect of temperature on the levels of moisture, ascorbic acid, proteins and phenolic compounds in green sweet peppers (cvs. Sumo and Quadrato d'Asti) was investigated after seven days' storage at a relative humidity of 85–90%. Chemical composition did not differ appreciably after storage at 10°C, whereas changes were found after storage at 20°C and 30°C. Therefore, 10°C was the most favourable storage temperature for peppers although, at 20°C, retention of quality was adequate in terms of texture and appearance.     

Effect of different packaging systems on the quality of tomato (Lycopersicon esculentum var. Rio Grande) fruits during storage

A packaging system is designed in our laboratory and evaluated for its suitability to extend storage life and improve the quality of tomato (var. Rio Grande) fruits at ambient temperature (Patent App. No. 484/2005). Freshly harvested mature green tomatoes were packed in polyethylene packaging with or without treating with calcium chloride, boric acid and potassium permanganate. The fruits were then evaluated for changes in quality parameters within the different stages of ripening. The treatments improved the storage life up to 96 days when compared with that of control (32 days). The results showed that within each ripening stage, the treated fruits remained better than that of control and all the ripening stages and treatments are significantly different ( P  < 0.05) from each other. It can also be deduced that treated fruits showed lower weight loss (%), total soluble solids (TSS) contents, acidity and spoilage incidence while ascorbic acid contents, sugar to acid ratio, flavour, texture, colour and overall acceptability were higher in treated fruits when compared with control at the red stage of ripening. Total sugars (%) were low in fruits treated with calcium chloride and boric acid with or without potassium permanganate.